Alkyl substituted thiophene sulfonic acid salts as detergents in mineral oil compositions



Patented Aug. 8, 1950 ALKYL SUBSTITUTED THIOPHENE SUL- FONIC ACID SALTSAS-D'ETERGENTS IN DHNERAL OIL COMPOSITIONS Orland M; Reifland Harry J.Andreas, In, Woudbury, N. 1., assignors to Socony-Vacuum Oil Company,Incorporated, a corporation of New York No Drawing. Application November20,1946,

' Serial N0. 711,212

. Claims. 101.252-33) This invention relates-to improved mineral oilcompositions and to new chemical conipounds for improving them. Morespecifically, this invention relates to mineral oil compositionscontaining salts of alkylated thiophene sulphonates in concentrationssuillcient to improve the properties thereof and to the .salts ofalkylated thiophene sulphonates per se. I

A number of oil-soluble detergents of the type of metal soaps,phenylates and alkylates have been proposed and used as crank case oilsto dissolve or disperse the sludge and prevent lacvquer deposits andstuck piston rings.

Unfortunately, however, the great majority of these substances increasethe rate of oxidation and their presence results in an increasedconcentration of acidic oxidation products in the oil. Increasedquantities of these acidic oxidation products in the oil create, inturn, an even more serious difllculty for they attack and corrode alloybearings commonly employed in internal combustion engines; Alloyscomposed of copper-lead, silvercadmium, nickel-cadmium, etc., are widelyused and are subject to attack by the acidic oxidation products formedin the oil.

Certain anti-corrosion agents which have no detergent properties havebeen added to lubri eating oils in order to counteract the corrosiveeffect of the oxidation products of the oil. Although many of thedetergents and the anti-corrosion agents which have been previouslymen-.

tioned perform their individual functions in lubrieating oils, the two,separate chemicals do not cooperate to produce a satisfactoryanti-corrosion and detergent action when used-together.

The function of a corrosion inhibitor is to cover thebearing surfacesand other corrodable parts of the engine with a passivating film that vprevents corrosion of the metal by the organic acids and other corrosiveproducts of the oil. A detergent, as its ;name implies, operates toremove adhering materials from the metal parts of the engine and thusproduce a clean metal surface. Consequently, heretofore known mixturesof a detergent with a corrosion inhibitor have 'proven to be ineffectiveover any extended period of time, since the detergent, action of thesludge inhibitor, tends, to remove the corrosion inhibitor from themetal surface, thus rendering it ineffective for the purposeintendecl;

In accordance with the present invention, a series of new compounds havebeen discovered, which compounds act in a highly satisfactory manner asdetergents and which at the same time 2 index of the oil. Furthermore,it has been discovered that these new compounds can be used incombination with anti-corrosion or stabilizing agents, without impairingthe effectiveness of either Mont.

THE OIL BASE The basic materials to which the improving agents of thisinvention are to be addedmay be generally described as minerallubricating oils of the type normally used in internal combustionengines. Such oils are generally produced from petroleum but may beproduced synthetically from other sources. It is contemplated that theprinciples of this invention may be applied to lighter petroleumproducts such as gasoline and kerosene or to heavier petroleum productsof the natureof petroleum gear lubricants, petroleum jellies andpetroleum waxes.

DETERGENT lat'ed thiophene sulphonates. In most cases these v will bemetal salts of alkylated thiophene sulphonates and when the metal ispolyvalent the salt may be either a neutral salt containing severalalkylated thiophene sulphonate radicals per molecule, or an alkalinesalt containing fewer radicals of alkylated thiophene s'ulphonate permolecule than are necessary to satisfy the valence of the metal, theremaining valences of metal being satisfied by carbonate or hydroxyradicals, or the like. Preferred, are the alkaline earth metal salts,examples of which are the barium, calcium and magnesium salts. For thepurpose of this specification, magnesium is included in the alkalineearth metal group.

The term thiophene as used in this specification, may be expanded toinclude thiophenelike materials, such as thionaphthene. Derivatives ofthese materials similar to the derivatives of thiophene, which will bespecifically disclosed, will function in a similar manner.

The thiophene radical of the new compounds is alkylated in at least oneposition and the alkyl substituent is preferably a long chain aliphatichydrocarbon group containing at least ten carbon atoms, such for exampleas the'alkyl radical obtained from paramn wax. Although there is noknown upper limit to the number of carbon atoms in the alwl chain, it ispreferred that there be not more than thirty. There are three places inthiophene sulphonate where the thiophene nucleus can be substituted andany improve the pour point of the oil and the viscosity as one or allthree of these places may have subaoiasva stituents. There appears to beno limit as to what these substituents can be, except that it isnecessary to have at least one alkyl substituent and it is preferred,mainly for reasons of oil solubility, to have at least one, relativelylong chain, alkyl substituent. The compounds will function, however, fortheir intended purpose,-even though the alkyl substituent is relativelyshort.

Concentrations in oil-of from about 0.5% to about of the new detergentagent are contemplated in this invention, but concentrations of from 2%to 5% have been found most satisfactory and hence are preferred.

STABILIZING AGENT -be prepared.

EXAMPLEI A paramn wax having an average of about 24 carbon atoms in themolecule and an ASTM melting point of about 126 F. was chlorinated atabout 100 C. with gaseous chlorine until the weight of the wax hadincreased by about 14%. The resultant chlorwax was then blown withthiophene and heated to about 80 C. and 36 g. of anhydrous aluminumchloride then added. The reaction mixture was stirred for 3 hours atabout 125 C. and then for 1 hour at about 165 C. The mixture was thencooled to about 100 C. and a large excess of water added to break up thealuminum chloride complex. The resultant mixture was filtered through alayer of absorptive clay and the product water-washed to free it ofhydrogen chloride and aluminum hydroxide. Thereafter it was topped at175 C. under 10 mm. of mercury pressure to give a wax alkylateddibutylthiophene.

To 547' g. of this product was added 91 g. of chlorsulphonic acid atroom temperaturefand the mixture was slowly heated to about 100 C. forabout 1 hour. The mixture was then cooled to about 75 C. and 123 g. ofbarium hydroxide octahydrate was added along with 200 g. of butylalcohol. This mixture was heated to about 165 C., filtered through alayer of absorptive clay and topped at 175 C. under 10 mm. of mercurypressure. The resultant product, a barium salt of wax substituteddibutyl thiophene sulphonate, was shown by analysis to contain about3.1% barium and about 5.2% sulphur.

EXAIHPLE'III 1004 g. of 14% chlorwax, prepared as described chloride wasadded, the temperature raised to nitrogen to remove any occludedhydrogen chloride or chlorine.

610 g. of the thus prepared chlorwax was stirred with 140 g. ofpowdered'calcium oxide for about 6 hours at about 255-265 C. and thenfiltered through a layer of absorptive clay, to give a product whichwill be referred to as unsaturated wax or wax olefin.

280 g. of the unsaturated wax were mixed with 100 g. of thiophene andabout 150 g. of a powdered synthetic silica-alumina gel catalystcontaining 7 to 15% alumina. The mixture was placed in an autoclave andheated to about 200 C. for 4 hours. A pressure drop of about 175 lbs.per square inch was observed. The reaction mixture was filtered througha layer of absorptive clay and topped at 175 C. under 10 mm. mercury ofpressure to give a product that is apparently a monowax alkylatedthiophene.

246 g. of the above wax alkylated thiophene,

were blended with 246g. of an SAE-lO grade motor oil and stirred at roomtemperature with 44.4 g. of chlorsulphonic acid for about 1 hour. Thetemperature was then slowly raised to about 100 C. and 50 g. of bariumhydroxide octahydrate were added along with about 200 g. of butylalcohol, to facilitate removal oi the water formed during the reaction.The reaction mixture was then heated to about 175 C. and filteredthrough a layer of absorptive clay. All traces of water and butanol wereremoved by distillation at about 175 C. under 10 mm. of mercurypressure. The product, a barium salt of wax alkylated thiophenesulphonate, showed, upon analysis, about 4.9% barium and about 2.8%sulphur, in the 1:1 oil blend.

EXAMPLE II about 110 C. and held for about hour. The mixture was furtherheated to about 175 C. for 1 hour to complete the reaction. The aluminumchloride complex was destroyed by adding an excess of water to themixture at about 100 C. and the resultant mixture was filtered through alayer of absorptive clay. All traces of hydrogen chloride and aluminumhydroxide were removed by thorough water-washing as before. The finishedproduct was obtained by topping the resultant mixture at about 175 C.under 10 mm. mercury of pressure. This product was apparently a diwaxalkylated methylthiophene. I

300 g. of this product was blended with 300 g. of SAE-lO grade mineraloil, and the mixture heated to 50 to 60 C. and 66.3 g. of chlorsulphonicacid then added. The temperature was thereafter raised slowly to about100 C. and held for 1 hour, then cooled to about C. and g. of bariumhydroinde octahydrate and 200. g. of butyl alcohol added and thetemperature again raised to about C. for 1 hour. As before, the mixturewas filtered through a layer of absorptive clay and topped at C. under10 mm. pressure to give the finished product. This product is apparentlya barium salt of diwax methylthiophene sulphonate showing upon analysis4.3% barium and 2.9% sulphur in the approximately 1:1 mineral oil blend.

EXAMPLEIV As an example of an antioxidant or stabilizing agent, that mayadvantageously be used in combination with the detergent agentsdescribed above, a pinene-phosphorus pentasulphide reaction product wasprepared in accordance with the disclosure of United States Patentapplication, Serial No. 482,482, filed April 9, 1943, by Fuller et a1.

According to this procedure a mixture of 800 g. of pinene and 800 g. ofa motor oil (SUV 45 seconds at 210 F.) was heated to 105 C. and

'nature of the reaction,

while stirring, 326.4 g. of phosphorus pentasulphide were added slowly,the temperature in- EXAMPLE V In order to illustrate the effectivenessof the new sulphonates in depressing the pour point of mineral oils,various percentages of the sulphonates made in accordance with ExamplesII and III were blended with a mineral oil having a Saybolt Universalviscosity of 67 seconds at 210 F. The following table shows the results:

Table I Conccili tra- ASTM P Improving Agent b Point, Weight None 0Product of Ex. II 1 -15 Do l5 Product of Ex. III 1 -30 Do L6 EXAMPLE VI7 Theviscosity index improvement that can be effected by the use of thenew sulphonates is illustrated by the following table which shows theresults of adding various concentrations of the products of Examples IIand III to a mineral oil similar to that used in Example V.

Lauson oxidation stability tests were conducted on certain blendscontaining both the sulphonates of this invention and the stabilizingagent described in Example IV, to determine the effectiveness of thestabilizing agent in the presence of the new sulphonates.

I The Lauson oxidation stability test is conducted in a Lauson singlecylinder, four cycle, liquid cooled gasoline engine with jetlubrication. A gallon sample of the product to be tested is added at thebeginning of the run and no oil is added during the test. 100% straightrun gasoline plus 2.5 cc. of tetraethyl lead is used as the fuel and thetest consists of operating the engine for 36 hours under standardconditions, and thereafter determining the neutralization number andkinematic viscosity at 210 F. of the oil.

During the test, the oil temperature is 280 F., the jacket temperatureof the engine is 212 F, the speed of the engine is 1815 R. P. M., thethrottle setting is A, and the fuel-air ratio'is 13:1.

In the test, the results of which are recorded in Table III, a minerallubricating oil having a Saybolt viscosity of 45 seconds at 210 F. wasused as the base 011. To this oil were added the materials indicated.

Table III Neutrall- Kinematic Improving Agent ration Viscosity No. at210 F.

None 10. 0 12. 71 4% of Product of Example I and of Product of ExampleIV 1. l 6. 98 4% of Product of Example III and of Example IV 1. 4 6.17

EXAMPLE VIII To further indicate the effectiveness of the new mineraloil compositions in internal combustion engine lubrication operationtests known as C. F. R. ring sticker tests, were conducted using a motoroil of seconds Saybolt Universal viscosity at 210 F. without anyaddition agents and with the addition of 4% of the sulphonate of ExampleIII and of the stabilizing agent of Example IV.

The C. F. R. ring sticker test is conducted in the C. F. R. fuel testengine modified for lubricant evaluation. This is a single cylinder,liquid cooled engine equipped to give controlled oil flow to thecrankpin. A one gallon sample of the product to be tested is added atthe beginning of the run and no oil is added during the test. Using 91octane no. aviation gasoline, the test is run for 28 hours with the oiltemperature at F., the jacket temperature at 390 F. and a speed of 1200R. P. M. The following items are reported: Actual number of degrees ofring sticking for all 5 rings; deposits in ring grooves of 3 oil rings;and total weight of deposits inside and outside of piston exclusive oflead deposits from gasoline.

Table IV.Ring condition EXAMPLE IX Indicative of the fact that the newdetergent agents are effective even in the presence of stabilizingagents are the results of a series of Lauson detergency tests.

The Lauson detergency test consists in operating a single cylinder, fourcycle, liquid cooled, jet lubrication, Lauson gasoline engine for 30hours, using gallon of the oil to be tested and then checking the oilfor neutralization number and the engine for cleanliness. The enginecleanliness is rated on a scale of 0 to 100, 100 representing aperfectly clean engine.

During the test, the engine is operated on 100% straight run gasolineplus 2.5 cc. of tetraethyl lead, no oil is added, the oil temperature is225 F., the jacket temperature 350 F., and the speed of the engine 1830R. P. M. The throttle setting is and the fuel-air ratio is 13:1.

In the following tests, a motor oil of 67 seconds 7 Saybolt Universalviscosity at 210 F. was used as the base oil.

It is contemplated by this invention that the new alkyl substitutedthiophene-like sulphonic acid salts will be incorporated in lubricatingoil compositions in amounts sumcient to improve the characteristics ofthe oils. It is further contemplated that such oils may contain astabilizing agent such as described in Example IVv or any otherstabilizing agent, pour point depressant, extreme pressure lubricationimproving agent, viscosity improving agent, or other agent that it isfound desirable to incorporate. It is also contemplated by thisinvention that the new alkyl substituted thiophene-like sulphonic acidsalts may be marketed per se, or in more concentrated admixtures withoil, which admixtures are adapted to be added to further quantities ofoil to improve its characteristics.

What is claimed is:

1. A mineral lubricating oil composition comprising a mineral oil and aminor proportion, sufiicient to improve the detergent properties of theoil, of an alkyl substituted thiophene alkaline earth metal sulphonicacid salt in which the 8 alkyl substituent contains a carbon chain aboutten to about thirty carbon atoms in length.

2. A mineral lubricating oil composition comprising a mineral oil and aminor proportion, sufllcient to improve the detergent properties of the'oil, of a petroleum wax substituted thiophene alkaline earth metalsulphonic acid salt.

3. A mineral lubricating oil composition comprising a mineral oil and aminor proportion, sufflcient to improve the detergent properties of theoil, 01 a petroleum wax substituted thiophene sulphonic acid bariumsalt.

4. A mineral lubricating oil composition comprising a mineral oil andbetween about .05% and about 10% of a petroleum wax substitutedthiophene sulphonic acid barium salt.

5. A mineral lubricating oil composition comprising a mineral oil andbetween about 2% and about 5% of a di-petroleum wax substitutedsulphonic acid barium salt.

ORLAND M. REIFF. HARRY J. ANDRESS, Jn.

REFERENCES CITED The following references are of record in the file ofthis patent:

Beilsteins Handbuch der Organischen Chemie, 4th ed. vol. XVIII, p. 570.

Whitmore: Organic Chemistry, 1937, p. 893.

Number

1. A MINERAL LUBRICATING OIL COMPOSITION COMPRISING A MINERAL OIL AND A MINOR PROPORTION, SUFFICIENT TO IMPROVE THE DETERGENT PROPERTIES OF THE OIL, OF AN ALKYL SUBSTITUTED THIOPHENE ALKALINE EARTH METAL SULPHONIC ACID SALT IN WHICH THE ALKYL SUBSTITUENT CONTAINS A CARBON CHAIN ABOUT TEN TO ABOUT THIRTY CARBON ATOMS IN LENGTH. 